How do we know God is a Trinity? Everything we know about God must be grounded in the truth of his word. God has written us a personal love letter in the pages of Scripture. Just as we might reveal things about ourselves in a letter to a loved one, God has revealed some things about himself in his letter to us. God tells us he is one and he tells us that he is three. Many would say that is a nonsensical statement. They would say he is either one or three, he cannot be both. The simple truth is that the Bible has clearly said God is both one and three. Over the next couple of weeks, we are going to think about what the Bible says that helps us know God is one and three. God is one. The most famous verse telling us this truth is Deuteronomy 6:4, “Hear, O Israel! The LORD is our God, the LORD is one!” This verse is the clearest statement of the truth that separated Israel from all of the other nations around them. Israel was monotheistic. That means they not only were supposed to trust in one God, they were supposed to believe in one God. Now, often they were guilty of breaking God’s command to believe only in him, but that doesn’t mean there are really any gods other than Yahweh, the one true and living God. Over and over throughout the Old Testament God reminds his people that he alone is to be worshipped. "Thus says the LORD, the King of Israel and his Redeemer, the LORD of hosts: 'I am the first and I am the last, and there is no God besides Me. Who is like Me? Let him proclaim and declare it; yes, let him recount it to Me in order; from the time that I established the ancient nation. And let them declare to them the things that are coming and the events that are going to take place. Do not tremble and do not be afraid; have I not long since announced it to you and declared it? And you are My witnesses is there any God besides Me, Or is there any other Rock? I know of none.'" (Isaiah 44: 6-8). The New Testament does not change the fact that God is one. James says, “You believe that God is one; You do well; the demons also believe, and shudder.” (James 2: 19) Even though Jesus is obviously God, and the Holy Spirit is God, never does the New Testament say, “You know, we were wrong, we thought there was one God, but now we see there are three.” That never happens because God has always been one and will always be one. Next week we will see from Scripture how He is three. In Christ, Blain Craig